Magnetic resonance imaging findings of the posterior fossa in 47 patients with mucopolysaccharidoses: A cross‐sectional analysis

Abstract

Background Mucopolysaccharidoses (MPS) is a group of hereditary multisystemic lysosomal disorders. Most neuroimaging studies in MPS have focused on the supratentorial compartment and craniocervical junction abnormalities, and data regarding posterior fossa findings are scarce in the literature. Thus, our purpose is to describe posterior fossa findings on magnetic resonance imaging (MRI) of MPS patients. Methods We reviewed routine MRI scans of MPS patients being followed up at our institution (types I, II, III, IV, and VI), focusing on posterior fossa structures. Results Forty‐seven MPS patients were included. MRI‐visible perivascular spaces were commonly found in the midbrain and adjacent to the dentate nuclei (85% and 55% of patients, respectively). White‐matter lesion was not identified in most cases. Its most frequent localizations were in the pons and cerebellum (34% and 30% of patients, respectively). Enlargement of cerebrospinal fluid (CSF) spaces in the posterior fossa was present in 55% of individuals and was more frequent in neuronopathic patients (73% vs 40%; P = .02). Cerebellar volume was classified as normal, apparent macrocerebellum, atrophic, and hypoplastic in 38%, 38%, 21%, and 3% of patients, respectively. A depression of the posterior fossa floor in the midline sagittal plane was found in 22 patients (47%), which was statistical significantly associated with enlargement of CSF spaces (P = .02) and with apparent macrocerebellum (P = .03). Conclusion The present study compiled the main posterior fossa findings in MPS patients. Classically described in the supratentorial compartment, MRI‐visible perivascular spaces, white matter lesions, and enlarged perivascular spaces were also found in the posterior fossa. However, atrophy, which commonly affects cerebral hemispheres, was not the most frequent cerebellar morphology found in our study. Moreover, potential findings for future research were described.

Cognitive and Behavioral Profile in a Child with Macrocerebellum—A Rare Congenital Brain Malformation

“…13 Three-fourth cases of MPS were reported to have normal or enlarged cerebellum, but other neuroimaging findings of enlarged perivascular spaces, cortical atrophy, white matter lesions, hydrocephalus, craniocervical junction abnormalities, and thickened middle cerebellar peduncles may be seen. 14 Patients with somatic mutations in PIK3CA are found to have increased brain cell growth causing MCAP and megalencephaly-polydactyly-polymicrogyria-hydrocephalus. Clinically, they have overgrowth of adipose, muscular, or skeletal tissue along with vascular malformations and epidermal nevus.…”

Severe Central Nervous System Demyelination in Sanfilippo Disease

“…While some case reports have indicated the presence of diffuse high-intensity signal in the white matter of MPS IIIA and IIIB patients [23,24], other studies reported an absence of white-matter lesions in most MPS III cases [25].…”

Severe central nervous system demyelination in Sanfilippo disease

“…Much less is known, however, about the white matter defects and, in particular, axonal pathology and demyelination in the MPS III patients. While some case reports have indicated the presence of diffuse high-intensity signal in the white matter of MPS IIIA and IIIB patients (Zafeiriou et al, 2001;Kara et al, 2008), other studies reported an absence of white-matter lesions in most MPS III cases (Reichert et al, 2021).…”